refs.c: abort ref search if ref array is empty

The bsearch() implementation on IRIX 6.5 segfaults if it is passed NULL
for the base array argument even if number-of-elements is zero.  So, let's
work around it by detecting an empty array and aborting early.

This is a useful optimization in its own right anyway, since we avoid a
useless allocation and initialization of the ref_entry when the ref array
is empty.

Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/refs.c b/refs.c
index c31b4616629b0c822ec03669e1e3091bb6d56403..cbc4c5d28d3252a3336cfa370cb3d720d5d8556d 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -110,6 +110,9 @@ static struct ref_entry *search_ref_array(struct ref_array *array, const char *n
        if (name == NULL)
                return NULL;
 
+       if (!array->nr)
+               return NULL;
+
        len = strlen(name) + 1;
        e = xmalloc(sizeof(struct ref_entry) + len);
        memcpy(e->name, name, len);